Commercially available frozen foods, such as ice cream, are packaged in cartons impervious to water vapor and odors. The cartons are usually fabricated of plastic coated paperboard erected to include four sides, a bottom panel and a hinged top cover having depending flanges overlying the upper edges of the sides.
A new form of carton for ice cream or the like has a removable paperboard flanged lid. The carton has short vertical flanges provided along the upper edges of the sides. When folded downwardly and inwardly along the margins of the carton mouth, a peripheral sealing area is defined. The separate lid covering the mouth engages the flanges and the upper edges of the sides to seal the contents.
The process of automatically filling and closing this new form of carton presents a unique lid seating problem to be solved. Specifically, after the erected cartons are filled with food product, the separately formed lids must be positively seated on the carton. Full sealing engagement with the carton flanges folded along the margins of the carton mouth must be attained.
The preferred apparatus and method for folding the flanges is disclosed in copending U.S. patent application Hoyrup, Ser. No. 283,553 filed July 15,1981, and assigned to the same asignee.
Especially where the cartons are filled with a liquid product, it is highly desirable to seat the flanged lids on the cartons during the lidding operation as gently as possible to avoid potential spillage of the product. This capability is lacking in the prior art.
The lids applied to seal the contents within the cartons are erected or formed in a lid forming machine. The lids are released from the forming machine upside-down and thus must be inverted before being applied to the cartons. It has proved difficult in the past to invert the lids while maintaining the high speed operation essential to efficient production. Utilizing prior inverting techniques, jamming can occur requiring manual repositioning and loss of valuable production time.
In many prior art machines, the lidding sequence is dependent upon precise timing and arrival of the lids and cartons to effect full seating engagement. Should improper timing occur, possible jamming of lids at the lidding station can result. A similar jamming problem can also result in the event of an empty flight (missing carton) on the carton conveyor. Thus, the requirement for precise, timed movement between the lids and cartons is a shortcoming of many prior art lidding machines and should be corrected.
Another difficulty encountered with prior art machines is that during the lidding sequence, the carton sides often tend to bow outwardly so as to preclude ready application of the lid to the carton. Correction of this problem has previously been attempted, but without success.